1. Field of the Invention
This invention relates to the field of consumer electronics, and in particular to a method and system for enabling playback devices to use playlists, or other forms of identification of select songs, from other systems.
2. Description of Related Art
The availability of entertainment material, such as audio recordings, continues to increase, particularly in view of the compression provided by particular encoding schemes, such as MP3. A single CD is able to store about 200 MP3-encoded songs; a DVD is able to store as many as 1500 MP3 songs. With the cost of storage devices continuing to decrease, it is not unusual for a person to have immediate access to thousands of songs. Home networking and network attached storage enable even greater accumulation of user content. Similar trends can be observed in car entertainment systems, as well as portable hard disk based players, such as iPod, by Apple. For example, home networking standard UPnP defines standard components of a home system that are enabled to stream, receive and control play-out, or playback, of content.
To facilitate the playback of select subsets of a user's collection, many playback devices allow the user to define such subsets, hereinafter termed “playlists”. A user may define a “favorites” playlist that contains an eclectic collection of songs that the user likes. Another playlist may be a “romantic” playlist that contains songs that the user prefers during a romantic interlude. Another playlist may be a “party” playlist that contains jovial and uplifting songs. Facilities are often available for automatically creating playlists, based on selected preferences of genre, artist, composer, etc. Facilities are also provided for searching one or more storage devices for select content material, such as all audio files, or all MP3 files, or all WINAMP-compatible files, and so on.
Each playlist generally contains an identification of the song and the artist, and an identification of the file that includes the song. When a particular playlist is selected, the playback system sequences through the songs that are identified in the playlist, retrieving the content material from each of the identified files. The sequence may be ordered or random, depending upon the user's preference at the time of playback.
A playlist may also be used to create a copy of content material corresponding to the playlist. That is, for example, a user may create a CD containing some or all of the songs that are identified in one or more selected playlists. Using the aforementioned categories of playlists, a user may create a “favorites” CD, a “romantic” CD, a “party” CD, and so on. Note that, because the location of the files containing the songs on the CD will be different than the location of the files that were used to provide the songs, the contents of a playlist for the songs on the CD differs from the contents of the playlist for the original songs. That is, although the same songs may be contained on the CD and at the original storage locations, when one playlist is used for playback, the songs will be accessed from the CD, and when the other playlist is used, the songs will be accessed from the original storage locations.
If a user desires to play songs from a playlist on another playback device, the user must transfer the content material corresponding to the playlist to the other playback device, either by transferring files via a communications network, or by the physical transport of removable storage media, such as a CD, DVD, MP3-player, and the like. This transfer must occur in order to provide the files corresponding to each entry in the playlist, regardless of the available content material that may exist at the other playback device.
FIG. 1 illustrates an example block diagram of a prior art system for the transfer of content material from a source system 110 to a destination system 160, based on a playlist A 140 at the source system 110. The playlist A 140 identifies particular content items 125 within a storage area 120 on the source system 110. The storage area 120 typically includes one or more non-volatile storage devices, such as disk drives or solid-state memory devices, and may include removable storage media, such as a CD, DVD, memory-stick, and so on. The playlist A 140 includes an identification of each content item 125 and an identification of the location of the content item 125 within the storage area 120 of the system 110.
To effect a transfer of the content material corresponding to the playlist A 140, the processing system 130 locates each content item 125 that is identified in the playlist A 140, and transfers a copy of each content item 125 to the destination system 160, as indicated by the dataset 150 from the source system 110. The dataset 150 may be transferred via a removable media that is transported from the source system 110 to the destination 160, or via a communications channel between the systems 110 and 160.
When the destination system 160 receives the dataset 150, the processing system 170 stores a copy 185 of the dataset 150 in a storage area 180 of the system 160. Alternatively, particularly in the case of the transfer of the dataset 150 via a removable media, the removable media may form the added element 185 of the storage area 180. As illustrated in FIG. 1, the copy 185 of the dataset 150, which is a copy of the content items 125, forms a discrete region of the storage area 180, typically as an added allocation of the storage area 180. To facilitate the playback of the copies 185 of the content items 125 in the storage area 180, the processing system 170 also creates a playlist B 190 that identifies the copies 185 of the content items 125 and their particular location within the storage area 180. The playlist B 190 substantially corresponds to the playlist A 140, except that the identification of the location of each content item 125 of the playlists A 140 and B 190 in the storage areas 120 and 180 differ.
As illustrated, to effect the transfer of a playlist A 140 of select content items 125, the prior art system of FIG. 1 requires a transfer of the dataset 150, regardless of other content items at the storage area 180.